Multi-chip package (MCP) or multi-chip module (MCM) technology refers to the practice of mounting multiple, unpackaged integrated circuits (IC's) (sometimes referred to as “bare dies”), along with required support circuitry, on a single base material, such as ceramic. The multiple bare dies are “packaged” within an overall encapsulation material, the encapsulation material generally comprising some type of polymide or other polymer.
MCP's often comprise some type memory IC, such as a double-data rate synchronous dynamic random access memory (DDR SDRAM) stacked over some type of logic IC, such as a microprocessor. By combining the microprocessor with the memory IC in this fashion, the MCP provides a high density module that requires less space in an electrical system, such as on the motherboard of a computer, than if the microprocessor and memory IC were individually packaged and mounted. Additionally, by consolidating multiple circuit functions in a single MCP, the electrical system in which the MCP is installed requires fewer system assemblies, thereby reducing system costs and further reducing system size. The MCP also provides the benefit of integrated functional testing.
While combining a logic IC's with a memory IC to form an MCP can reduce system space requirements and the number of system assemblies, logic IC's are generally high power devices and generate a large amount of heat relative to memory IC's. The heat generated by the logic IC can heat the entire MCP and can negatively impact the performance of the memory IC, which is often designed with a lower maximum operating temperature than the logic IC. If the maximum operating temperature of the memory IC is exceeded, propagation delay within the memory IC may increase and the memory IC may not be able to operate at certain clock frequencies, potentially resulting in data errors and system failure.